Numerade

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Example 7.4 When a steady wind blows past the hanging wires of a bridge, vortices are generated on the downwind side of the wires, which are shed regularly at a definite frequency, as shown in the figure. If this frequency coincides with the natural frequency of the bridge, then harmful periodic forces will be created on the bridge. For this reason, it is very important to determine this shedding frequency for hanging wires having a diameter of 0.1 m when the wind is blowing steadily at $ 20 \mathrm{~m} / \mathrm{s} $. To determine the shedding frequency, a model of these wires having a diameter of 0.02 m is tested in the water tunnel and the shedding frequency is found to be 40 Hz . Determine the shedding frequency for the prototype. The viscosity and density of air are $ 1.8 \times 10^{-5} \mathrm{~Pa} $.s and $ 1.2 \mathrm{~kg} / \mathrm{m}^{3} $, respectively, while the viscosity and density of the water are $ 0.001 \mathrm{~Pa} . \mathrm{s} $ and $ 1000 \mathrm{~kg} / \mathrm{m}^{3} $, respectively.

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A metal ball with unknown mass and radius R = 7.0cm is suspended from the ceiling using a spring with k = 170 N/m. The ball is positioned directly above a bucket filled with wa- ter (ρw = 1,000kg/m3), and it is completely submerged and motionless. Suppose that we drain all of the water out of the bucket and replace it with ethanol (ρe = 790kg/m3) so that the ball is again completely submerged and motionless. What is the change in height ∆h of the ball? Be sure to clearly indi- cate whether the ball has ascended or descended. For the limit check, investigate what happens to ∆h if the ethanol becomes extremely watered down (i.e., ρe → ρw). Representation Representation: Physics Concept(s): Initial Equation(s): Symbolic Answer: Units Check: Limits Check: Neatness: -2 Total: Correct Answer: Y N 0 0 0 0 1 1 2 1 2 0.5 1 0 0 0.5 1 0.5 1 -1 0 Physics Concept(s) (Refer to the list posted on Carmen) (1) (2) Initial Equations ↓ Show Your Equation Work On Next Page ↓ Algebra Work (Symbols only. Don’t plug in any numbers yet.) Symbolic Answer: Unit Check Limit Check a) As ρe → ρw, what limit does ∆h approach? b) Why does the result make physical sense? Numerical Answer: (Obtain this by plugging numbers into your symbolic answer.)

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Match the following unit prefixes with the correct associated exponent value. Prompt 1centi Answer for prompt 1 centi Prompt 2micro Answer for prompt 2 micro Prompt 3kilo Answer for prompt 3 kilo Prompt 4milli

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Which of the following statements are true? C++ allows you to separate class declaration from implementation. The class declaration describes the contract of the class, and the class implementation implements the contract. The class declaration and implementation are often in two separate files. Both files should have the same name, but with different extension names. The class declaration file has an extension name .h and the class implementation file has an extension name .cpp. All of the above.

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Find the derivative.\\ $\frac{d}{dx} \left(\sqrt[3]{x} - \frac{5}{x}\right)$

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2.2. The normalized wave function is given as \[ \psi(x)=\frac{\sqrt{31}}{2 a^{\frac{3}{2}}}\left(a^{3} x^{\frac{3}{2}}-x^{\frac{5}{2}}\right) \] and is present in 1D potential well given as Figure 1: Find the ground state energy using the expectation value $ \langle E\rangle $.

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Temperature °C 0 10 20 30 40 50 60 70 80 90 100 2400 2200 2000 1800 3 1600- 1541°C 1400- 1 1277°C 1200 ?-? 2 AB2 2250°C Atom % B L 7 10 2092°C 2040°C 5 2003°C 85 6 1877°C 54 ?-? 9 4 AB12 8 1000 800 0 10 20 30 40 50 60 70 80 90 100 A Weight % B B (a) Label the fields 1-10 in the A-B alloy phase diagram above. [10 points] (b) Write down the three eutectic reactions in the alloy phase diagram. [15 points] 1 (c) Find the composition of the alloy that is 50% L and 50% AB$_{12}$ at 1900 °C. Is this alloy hypoeutectic or hypereutectic? What is the primary phase in this alloy? [15 points]. Hint: assume the alloy composition is x and then solve using the lever rule. (d) Determine the phases, their compositions, and the weight fractions of the phases in this alloy of point c above at 1600°C. [15 points] (e) Draw schematically the microstructure of this alloy of point c above at 1600 °C. [5 points]

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What is the pH of 0.80 M Hypobromite acid (HBrO) which is a weak acid? The Ka the weak acid is 4.5 x 10$^{-8}$. Hint: $HBrO(aq) \leftrightarrow H^{+}(aq) + BrO^{-}(aq)$ $[i], M$ 0.80 0 0 $[C], M$ -X +X +X $[E], M$ 0.80 - X X X $K_{a} = \frac{(X)(X)}{0.80 - X}$ Hint: Solve for $(X) = [H^{+}]E$ Then: $[H^{+}]$ at Equilibrium then $pH = -Log[H^{+}]E$ A. pH = 3.2 B. pH = 3.4 C. pH = 3.6 D. pH = 3.7 E. pH = 4.2

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Airline industry is being heavily impacted by COVID-19 pandemic. Without any government support it will be hard to stay in business for some companies in this industry. In your opinion, which is supported by the existing data, • what is the current standings of US/Global Airline industry? • analyze government support that was provided to that industry in the US. • Provided government support and current trends in the market, is it correct to assume that government bailed out airline industry? What could be an implication if that support was not granted? (look at historical trends/similar cases and for different industries)

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1. A worker receives a whole-body dose of 0.10 mGy from 2 MeV neutrons. Estimate the dose equivalent. You need to determine the appropriate W to perform this simple calculation.

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alfredo n.